1. Field of the Invention
The present invention relates to a method for controlling the deformation of a surface of a sail of a sailing boat during a direction change maneuver, specifically a veer or a jibe.
The invention also relates to a sail for a sailing boat and to a batten for such sail, such sail and such batten allowing the above method to be carried out.
2. Description of the Related Art
Preferably, but not exclusively, the method is carried out by a crew of a racing sailing boat, such as an America's Cup class boat. The sails and the battens of the present invention are thus intended to be preferably but not exclusively used on such type of boats.
Throughout the following description and appended claims, the word: veer, is used to indicate a direction change maneuver with substantially fore wind, adapted to bring the boat to get wind on the side opposite that where it gets wind before the maneuver is carried out, while the word: jibe, is used to indicate a direction change maneuver with substantially aft wind, adapted to bring the boat to get wind on the side opposite that where it gets wind before the maneuver is carried out.
As known, in sailing boats, especially in racing sailing boats, the use of sails provided with suitable stiffening battens is diffused; this is to improve the boat performance and speed during the race.
The sails provided with battens are, for example, the mainsail, the genoa and the jib.
The battens are housed into respective seats or pockets formed on the side surfaces of the sails and have the function of imparting desired bending stiffness and/or aerodynamic properties to the sails, when unfurled, while offering at the same time the largest sail surface to the wind. Typically the battens, in the top portion of the sails, allow forming the roach that allows to increase the surface of the sail exposed to the wind and thus to improve the boat performance and speed.
Specifically, in the genoa, the battens have the function of imparting a desired bending stiffness to the sails and of preventing the flapping of the after leech; in that case, therefore, the battens follow the sail profile imposed by the wind, offering to the wind a sail surface as largest as possible. Typically, four or five battens are used in the genoa, of which at least three are arranged in the top portion of the sail, where the after leech has a strong roach, and one or two battens in the bottom portion of the sail, where the after leech is straighter.
In the mainsail, on the other hand, the battens have the function of enhancing the sail aerodynamic properties imparting the desired shape thereto.
Generally, the battens used in the sails of racing sailing boats are made of composite materials, such as resins reinforced with glass or carbon fibres.
GB 2354218 discloses a stiffening batten for a sail, comprising an inflatable pipe provided with means for attaching to the sail edge. The inflatable pipe is made, for wide sails, of reinforced elastomeric material and for small sails, of polymeric material, preferably PVC or polyethylene.
WO 94/14648 discloses an inflatable sail batten, in particular for a mainsail intended to be wound inside the boat mast. The batten is arranged in a special pocket formed on the sail. The batten consists of a fluid-impervious flexible tube having sealed opposite ends. At one of these ends, a small tube communicating with the interior of the flexible tube is connected to a supply tube extending along the sail edge. The supply tube is connected to a valve for inflating the batten. The fluid-impervious flexible tube of the batten consists of an inner layer of nylon or polyester coated with an outer layer of polyurethane; optionally, the tube may be made of polyurethane or rubber coated with a woven fabric.